Hello!

(I am still unsubscribed, see my mail from 31.3.2015, so CC me on any answers.)

I bought Samsung Evo+ MicroSDXC 128GB. It was formatted with ExFAT. I formatted it with FAT32 and Rockbox worked out of the box with it.

I kept the partition table. I think they let the first partition start at sector 32768 (instead of Linux default 2048) for a (performance) reason.

Samsung-Evo+-MicroSDXC-128GB> somepath/flashbench.git/flashreport /dev/mmcblk0

===> MMC card detected with erase block size of 524288 bytes <=== ==> find /sys/block/mmcblk0/device/ -maxdepth 1 -type f | xargs head <==

==> /sys/block/mmcblk0/device/cid <== 1b534d3030303030101b55022500fb00

==> /sys/block/mmcblk0/device/csd <== 400e00325b590003bdfd7f800a400000

==> /sys/block/mmcblk0/device/scr <== 0245800300000000

==> /sys/block/mmcblk0/device/date <== 11/2015

==> /sys/block/mmcblk0/device/name <== 00000

==> /sys/block/mmcblk0/device/type <== SD

==> /sys/block/mmcblk0/device/preferred_erase_size <== 4194304

==> /sys/block/mmcblk0/device/fwrev <== 0x0

==> /sys/block/mmcblk0/device/hwrev <== 0x1

==> /sys/block/mmcblk0/device/oemid <== 0x534d

==> /sys/block/mmcblk0/device/manfid <== 0x00001b

==> /sys/block/mmcblk0/device/serial <== 0x1b550225

==> /sys/block/mmcblk0/device/uevent <== DRIVER=mmcblk MMC_TYPE=SD MMC_NAME=00000 MODALIAS=mmc:block

==> /sys/block/mmcblk0/device/erase_size <== 512

==> fdisk -lu <== Festplatte /dev/mmcblk0: 119,8 GiB, 128579534848 Bytes, 251131904 Sektoren Einheiten: Sektoren von 1 * 512 = 512 Bytes Sektorgröße (logisch/physikalisch): 512 Bytes / 512 Bytes E/A-Größe (minimal/optimal): 512 Bytes / 512 Bytes Festplattenbezeichnungstyp: dos Festplattenbezeichner: 0x00000000

Gerät Boot Anfang Ende Sektoren Größe Kn Typ /dev/mmcblk0p1 32768 251131903 251099136 119,8G 7 HPFS/NTFS/exFAT

==> sfdisk -d <== label: dos label-id: 0x00000000 device: /dev/mmcblk0 unit: sectors

/dev/mmcblk0p1 : start= 32768, size= 251099136, type=7

===> Partition details <===

==> sudo file -sk /dev/mmcblk0 <== /dev/mmcblk0: DOS/MBR boot sector; partition 1 : ID=0x7, start-CHS (0x2,10,9), end-CHS (0x3ff,254,63), startsector 32768, 251099136 sectors, extended partition table (last) DOS/MBR boot sector\012- data

==> sudo file -sk /dev/mmcblk0p1 <== /dev/mmcblk0p1: DOS/MBR boot sector DOS/MBR boot sector DOS executable (COM), boot code\012- data

==> head -c20M | hexdump -C<== 00000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 000001b0 20 14 09 10 4d 00 00 00 00 00 00 00 00 00 00 0a | ...M...........| 000001c0 09 02 07 fe ff ff 00 80 00 00 00 78 f7 0e 00 00 |...........x....| 000001d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 000001f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 00000200 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 01000000 eb 76 90 45 58 46 41 54 20 20 20 00 00 00 00 00 |.v.EXFAT .....| 01000010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 01000040 00 80 00 00 00 00 00 00 00 78 f7 0e 00 00 00 00 |.........x......| 01000050 00 40 00 00 00 40 00 00 00 80 00 00 f8 f6 0e 00 |.@...@..........| 01000060 04 00 00 00 bd 6b 33 9c 00 01 00 00 09 08 01 80 |.....k3.........| 01000070 00 00 00 00 00 00 00 00 f4 f4 f4 f4 f4 f4 f4 f4 |................| 01000080 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 |................| * 010001f0 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 55 aa |..............U.| 01000200 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 010003f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 01000400 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 010005f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 01000600 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 010007f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 01000800 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 010009f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 01000a00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 01000bf0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 01000c00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 01000df0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 01000e00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 01000ff0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 01001000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 010011f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 01001200 46 7e 0c 0a 99 33 21 40 90 c8 fa 6d 38 9c 4b a2 |F~...3!@...m8.K.| 01001210 00 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 01001220 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 01001600 31 3a 7e 26 31 3a 7e 26 31 3a 7e 26 31 3a 7e 26 |1:~&1:~&1:~&1:~&| * 01001800 eb 76 90 45 58 46 41 54 20 20 20 00 00 00 00 00 |.v.EXFAT .....| 01001810 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 01001840 00 80 00 00 00 00 00 00 00 78 f7 0e 00 00 00 00 |.........x......| 01001850 00 40 00 00 00 40 00 00 00 80 00 00 f8 f6 0e 00 |.@...@..........| 01001860 04 00 00 00 bd 6b 33 9c 00 01 00 00 09 08 01 80 |.....k3.........| 01001870 00 00 00 00 00 00 00 00 f4 f4 f4 f4 f4 f4 f4 f4 |................| 01001880 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 |................| * 010019f0 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 f4 55 aa |..............U.| 01001a00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 01001bf0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 01001c00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 01001df0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 01001e00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 01001ff0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 01002000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 010021f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 01002200 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 010023f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 01002400 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 010025f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 01002600 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 010027f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 01002800 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 010029f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 01002a00 46 7e 0c 0a 99 33 21 40 90 c8 fa 6d 38 9c 4b a2 |F~...3!@...m8.K.| 01002a10 00 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 01002a20 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 01002e00 31 3a 7e 26 31 3a 7e 26 31 3a 7e 26 31 3a 7e 26 |1:~&1:~&1:~&1:~&| * 01003000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 01400000

===> Trying to find erase block size by read tests <===

==> sudo flashbench -a --count=100 --blocksize=1024 /dev/mmcblk0 <== align 34359738368 pre 4.87ms on 5.29ms post 4.07ms diff 825µs align 17179869184 pre 5.21ms on 5.68ms post 4.13ms diff 1.01ms align 8589934592 pre 5.21ms on 5.66ms post 4.16ms diff 974µs align 4294967296 pre 4.1ms on 4.52ms post 4.17ms diff 377µs align 2147483648 pre 4.03ms on 4.36ms post 4.07ms diff 309µs align 1073741824 pre 4.06ms on 4.37ms post 4.11ms diff 286µs align 536870912 pre 4.05ms on 4.37ms post 4.09ms diff 303µs align 268435456 pre 4.06ms on 4.4ms post 4.12ms diff 310µs align 134217728 pre 4.07ms on 4.4ms post 4.1ms diff 316µs align 67108864 pre 4.06ms on 4.39ms post 4.11ms diff 302µs align 33554432 pre 4.12ms on 4.45ms post 4.09ms diff 344µs align 16777216 pre 4.1ms on 4.44ms post 4.08ms diff 355µs align 8388608 pre 4.04ms on 4.37ms post 4.07ms diff 313µs align 4194304 pre 4.01ms on 4.35ms post 4.1ms diff 292µs align 2097152 pre 4.03ms on 4.37ms post 4.1ms diff 303µs align 1048576 pre 3.99ms on 4.34ms post 4.05ms diff 323µs align 524288 pre 4.01ms on 4.37ms post 4.05ms diff 343µs align 262144 pre 4.03ms on 4.37ms post 4.06ms diff 326µs align 131072 pre 4ms on 4.35ms post 4.05ms diff 325µs align 65536 pre 3.98ms on 4.34ms post 4.04ms diff 331µs align 32768 pre 4.02ms on 4.34ms post 4.07ms diff 299µs align 16384 pre 3.96ms on 3.96ms post 3.95ms diff 5.47µs align 8192 pre 4.02ms on 4.02ms post 4.02ms diff 2.83µs align 4096 pre 3.98ms on 3.96ms post 3.97ms diff -18507n align 2048 pre 4.04ms on 4.04ms post 4.02ms diff 5.11µs

(See README for an explaination on how to interpret the values.)

Medium is a memory card which reports 524288 bytes as erase block size and 4194304 bytes as preferred erase size.

===> Suggestions for further benchmarking <===

Further tests can show the number of open erase blocks the medium can support.

BEWARE: These tests write onto the device! Make a backup first!

Further tests could look as follows: flashbench --open-au --open-au-nr=3 --erasesize=524288 --blocksize=1024 /dev/ mmcblk0 --offset=$[24*1024*1024] flashbench --open-au --open-au-nr=5 --erasesize=524288 --blocksize=1024 /dev/ mmcblk0 --offset=$[24*1024*1024] flashbench --open-au --open-au-nr=7 --erasesize=524288 --blocksize=1024 /dev/ mmcblk0 --offset=$[24*1024*1024] flashbench --open-au --open-au-nr=13 --erasesize=524288 --blocksize=1024 /dev/ mmcblk0 --offset=$[24*1024*1024]

(Consult the README for further suggestions.)

I didn´t run the additional tests.

Thanks,